Fix sup_delayed_restart_SUITE.

To accommodate changes made in rabbitmq/rabbitmq-common#201.

Author: aartamonau

test/sup_delayed_restart_SUITE.erl

@@ -81,6 +81,7 @@ exit_child(SupPid) ->
 with_child_pid(SupPid, Fun) ->
     case supervisor2:which_children(SupPid) of
         [{_Id, undefined, worker, [?MODULE]}] -> ok;
+        [{_Id, restarting, worker, [?MODULE]}] -> ok;
         [{_Id,  ChildPid, worker, [?MODULE]}] -> Fun(ChildPid);
         []                                     -> ok
     end.